To put it simply, yes, to all of the above...Secunia, MS-DCU and some others put out some excellent information on Twitter.  But you have to careful who you follow or you'll get Ashton Kutcher's answer for the question of life, the universe and everything.  Or you'll get $h!t my Dad says...

I pretty much agree with what you've written here. The way I see it, you're better off having 30 engaged, intelligent followers then 23000 followers who are just trying to get a high score.

Yes, there are some people saying important/interesting things (I like to believe I am one of those people on occasion) but for the most part it's like being in a packed conference with everyone shouting to be heard.

I have asked these same questions after being on Twitter for about a year.. I am off it now.. Never found the value in following or sending